Droplet actuators are used to conduct a wide variety of droplet operations. A droplet actuator typically includes one or more substrates forming a droplet operations surface or droplet operations gap. The gap between the substrates is typically filled with a filler fluid that is immiscible with the liquid that is to be subjected to droplet operations. Droplet operations are controlled by electrodes associated with one or both of the substrates. There is a need for modified droplet actuators and droplet actuator techniques for manipulating beads on a droplet actuator.